How much cache is recognized by the system now?

Filosofia wrote on 2020-10-31, 17:26:

20201030_162835.jpg

Polulated with 8 chips but I only have one tag ram left. Put it on one of the three available slots. Does not work. What can I do?

Left side, second chip from below 1 pin is not in socket. You put it wrong!!!

kixs wrote on 2020-10-31, 17:38:

How much cache is recognized by the system now?

none 🙁

danijelm wrote on 2020-10-31, 17:46:

Filosofia wrote on 2020-10-31, 17:26:

20201030_162835.jpg

Polulated with 8 chips but I only have one tag ram left. Put it on one of the three available slots. Does not work. What can I do?

Left side, second chip from below 1 pin is not in socket. You put it wrong!!!

Indeed! Thanks!
Still, system does not recognize L2 at all

I also notice the E63 socket isn't big enough to hold the chip you have inserted. The overhanging pins are I/O2,3,4 and GND. That is not going to work. Do you have a manual for this board? Or at least its model number? Failing that, can you take a picture of the whole board?

The tag? chip (E63) doesn't look very healthy

Is it just me or you are trying to install a DIP28 chip into 24 pin socket? Surely it can't work like it is installed.

mpe wrote on 2020-10-31, 21:27:

The tag? chip (E63) doesn't look very healthy

Is it just me or you are trying to install a DIP28 chip into 24 pin socket? Surely it can't work like it is installed.

yeah, that's why I'm asking for the manual. Do you think maybe two of the three sockets are designed to hold a pair of 16kx4s or 8kx8s to make up the tag ram? I suspect the third socket is for a dirty ram, looking at the SiS 461 datasheet, it appears to need a separate one and can't do dirty in tag.

edit: Looks like 64Kx4 SRAM (MT5C2564) came in a 24-pin package

Looks nearly identical to the DECPC LPX as for Cache sockets, jumpers and two VLB slots (from what little I can see in the photo): https://th99.infania.net/m/C-D/34204.htm
Needs 3 - 16k x 4 (64K) TAG chips. Without the TAG chips the board will not see/use the main cache chips.
If it is the DECPC LPX board page 63 of the manual has the Cache upgrade info: http://www.vogonsdrivers.com/getfile.php?fileid=1736

Thank you. It is a dec pc lpx yes. Will have to find those 3 tag chips. Any recomendations?

Wow those 16k x 4 are hard to find ! 64K in 64k x1, 8k x8 and 4 x 16K are a bit more common SRAM. I looked thru Digikey and Mouser and found nothing for 16k x 4.
Wonder if 16k x 8 would work if in 24pin and same pinout.... though they are very expensive. Too bad the manual does not give some relative part numbers that could be cross referenced.

Horun wrote on 2020-11-02, 02:34:

Wow those 16k x 4 are hard to find ! 64K in 64k x1, 8k x8 and 4 x 16K are a bit more common SRAM. I looked thru Digikey and Mouser and found nothing for 16k x 4.
Wonder if 16k x 8 would work if in 24pin and same pinout.... though they are very expensive. Too bad the manual does not give some relative part numbers that could be cross referenced.

Yeah, worse it looks like they come in two pinout styles - MT5C6404 (22-pin) and MCM6290C (24-pin), looks like difference is whether there is an output enable.
I wonder why they used those 16kx4 chips instead of a 32kx8. Do you think they were easier to find in 20 ns speed at the time the machine was made?

Horun wrote on 2020-11-02, 02:34:

Wow those 16k x 4 are hard to find ! 64K in 64k x1, 8k x8 and 4 x 16K are a bit more common SRAM. I looked thru Digikey and Mouser and found nothing for 16k x 4.
Wonder if 16k x 8 would work if in 24pin and same pinout.... though they are very expensive. Too bad the manual does not give some relative part numbers that could be cross referenced.

😭